1. Field of the Invention
This present invention generally relates to the field of semiconductor power devices. More particularly, the present invention relates to a semiconductor power device with a super junction.
2. Description of the Prior Art
A power device is used in power management; for example, in a switching power supply, a management integrated circuit in the core or peripheral region of a computer, a backlight power supply, and in an electric motor control. The type of power devices described above include an insulated gate bipolar transistor (IGBT), a metal-oxide-semiconductor field effect transistor (MOSFET), and a bipolar junction transistor (BJT), among which the MOSFET is the most widely applied because of its energy saving properties and ability to provide faster switching speeds.
In a conventional power device with a super-junction, a high voltage device is disposed in a cell region surrounded by a junction termination region. In general, concentric ring-shaped trenches surround the cell region layer-by-layer and function as a voltage sustaining structure in the termination region. During a regular operation of the device, however, the voltage sustaining structure is usually not robust enough to sustain a high voltage resulting from a source region for a long time. As a consequence, the phenomenon of an electrical breakdown occurs and the efficiency of the device is reduced. Accordingly, there is a need for providing a voltage sustaining structure which can improve the voltage sustaining ability and further ramp up the reliability of the device.